RoadTest: :MOVE mini buggy kit + microbit
Evaluation Type: Electromechanical
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: This is a similar produce to the Raspberry Pi + STS-Pi
What were the biggest problems encountered?: Difficulty in calibrating wheel speed to be the same. No indication when power is on - easy to run batteries flat.
I run a Code Club for 9-10 year olds at my local school and I've been looking for some time to introduce some robotic element that is accessible to this age group and has good teaching value. For this reason I signed up to road test a Kitronik :MOVE mini. I had previously purchased an STS-Pi robot for this but found it too complex to introduce to this age group and format.
As I will use the :MOVE mini as a teaching tool I'll be paying particular attention to the following:
For this road test I received a Kitronik :MOVE mini robot and a BBC micro:bit (you would need to purchase these separately).
Unpacking the boxes comes supplied with a 31 page instruction booklet and all the components nicely packaged in bags (I removed the board from anti-static bags for the photo):
I was very impressed by the quality of booklet, I was expecting a rather simple assembly instructions but instead found detailed steps on how to both assemble the robot and use the micro:bit. It would be suitable for someone without prior experience in either.
Following the instructions the first step is to assemble the SERVO:LITE board. This is the board that allows the micro:bit to drive the servos. This is also available as a stand-alone product if you wanted to make other projects using servos. The only tools required were a small Phillips screwdriver and a full cup of tea, and I had both readily available already. The micro:bit is attached using 5 screws which also serve to make the electrical connection between the micro:bit and the SERVO:LITE. This seems like quite a nice solution, but it does have the downside that the micro:bit is not as easily removed if an edge connector had been used instead. In a classroom scenario it would be nice to be able to make best use of your micro:bits by moving them between projects.
I expected step 2 of the instructions to be more robot assembly but it was actually about programming the assembled SERVO:LITE board. This a really nice idea, because it meant it taught you some basic micro:bit programming and ensured the board was working before continuing. The other steps of the instruction continued this style of switching between building the robot and programming it. I think this would help people assembling it get a really good understanding of how it worked and the variety would help avoid the project being frustrating. This step programmed the lights which were both bright and colourful.
The next step involved assembling the wheels and calibrating the servos that drive them. Out of the box one of my servos turned when it should have been stationary so I adjusted the a screw as shown in the instructions and this fixed it. However, while the instructions mentioned it briefly I didn't carefully calibrate the servos so they ran at the same speed. Due to their location in the robot later on these calibration screws are not accessible without disassembling the robot. This is somewhat frustrating to find out after assembling everything - I think the instructions could be updated to help here.
The final steps were to assemble the chassis. The parts were reasonably easy to fit together and felt very strong. The hardest part was getting the very small nuts into the provided slots to make the T-joints. I can imagine this will be quite frustrating for many people (persist!).
With the bolts tightened it was complete! Assembly took me around 1-1.5 hours. I think the final product looks very cute and sturdy enough to survive a few crashes. Using the supplied code I was able to test the movement and glad to see it worked well on both smooth and carpeted surfaces. Using the pen-holder in the top I could confirm you can very easily draw circles and squares.
Now was the time to put away the supplied instructions and try my own project. The goal was to use a second micro:bit to control the :MOVE mini. I very quickly had the A and B buttons on the turning the left and right wheels on and off. It was very rewarding to have the transmitting micro:bit using a battery pack and be able to drive the :MOVE mini across my lounge carpet. As an improvement I changed the controller to set the speed using A and B and use the tilt sensor to control the turning. With this I could control drawing on a piece of paper. I like that there is an easy progression from simple controls to move advanced ones and I think this will make this a great learning tool.
There was one hiccup that did occur during this road test. I did the testing over two nights and on the second night the :MOVE mini had flat batteries due to me accidentally leaving the power switch on. I think this is a deficiency in the design - there's no visual indication when the power is on and the switch is very small. So I can imagine a lot of wasted batteries with these especially in a school environment. I think the design needs an LED to indicate power state. I have since done this a second time (I definitely need not get some rechargeable batteries).
While I got my :MOVE mini for free for this test the price is approximately twice the cost of a micro:bit board. Due to this and the fact the micro:bit is not easily removed this makes this a reasonably expensive piece of equipment. For a club like ours we'd be more likely to share a few robots rather than have a full class set.
And now it was time to introduce the :MOVE mini to the real critics... the students. I introduced the :MOVE mini into my Code Club as the tenth and final project for the term. This meant the kids had a good grasp of micro:bit basics by the time they started to use it and it motivated the other kids to complete the early projects so they could use it too. The first two kids to reach the :MOVE mini project happily spent the next lesson (one hour) working mostly self directed with it. I observed:
Nothing was broken by the end of the lesson so I rate this as kid safe.
In summary this is a really good product to introduce basic robotics with a BBC micro:bit. The instructions exceeded my expectations and the build quality was good. The main two issues were the calibration of the wheel speeds and accidentally running the batteries flat. I'd recommend this product for those teaching kids programming. Thanks to Element 14 for giving me this opportunity to test this fun little robot!